Questions about Geothermal

[shigadeyo]

We have a 20 year old, 2-story, 2000 square foot (finished) house with a ~1000 square foot currently unfinished basement. Right now I have an electric heatpump that is old, grossly under-sized, and produces HUGE electric bills. We are getting ready to pull the trigger on a WaterFurnace Envision Dual Compressor unit to replace the existing equipment. We will also be getting a complete duct overall since the current stuff is really screwed up. I have a couple questions that I am looking for suggestions/comments/advice:

1. One contractor is recommending a 3-ton Dual Compressor unit with a 4 ton loop (vertical closed). Another is recommending a 4-ton Dual Compressorunit with a 4 ton loop (vertical closed). Seems like a big difference in equipment and was wondering if the extra cost to operate a 4 ton unit is worth it. What is a good loop operating temperature?

2. Bypass humidifer (AprilAire 600), steam humidifier, or other? I would like appropriate comfort to reduce dry skin, etc. but don't want a huge extra monthly electric cost. Also, depending on the type, what is the best placement for it (supply vs. return).

3. Get the standard 2" MERV-11 disposable filters that come with the WaterFurnace or upgrade to a HEPA-like filter for better filteration, but a higher cost?

4. We currently have a new 80-gallon electric water heater, is another tank or anything necessary to ensure enough hot water.

5. Two zones are currently proposed: 1 for the 2nd floor and 1 for the 1st floor and basement (to be finished). Is this okay or should the basement be on a separate zone? Is it worth the extra thermostat and ducting cost if dampers can be used?

6. 4 vertical wells are currently proposed in a box layout, 10-12 feet from garage and 10-12 feet between holes in order to avoid surrounding trees. I believe that the depth of the holes are to be 150' each. Is there enough distance between the holes?

I think that's it for now. I'll update or reply with any additional questions.

Thanks for the help!

[jerryd_2008]

What are HUGE bills and where are you? Have you addressed any house issues first? Would be unpleasant to put in an expensive geo or any other unit to find that it didn't solve your problems.

I will give my observations as a HO that was hot to put in geo with hot water recovery. Make sure you understand it. It's more complicated with wells than any other system I looked at. Determine how long you will live there. Find very experienced contractors. Compare your actual geo proposal costs after all credits and rebates against high end HP (or DFHP) actual costs after all credits and rebates. After all of the trying to force fit geo to my situation, I finally ran the numbers and given our energy lifestyle I could not justify it and probably wouldn't recover the extra cost in our lifetime. You may be able to but prove it!

[INTECHBILL]

jerryd 2008 is right don't spend it until your ready.. The 20 year old home was built less eff. than the ones today and you already have questions with regards to the contractors choice.. By all means you need a detailed Manual J heat gain - heat loss calculation to be done the contractor should offer you this... have your electrical service evaluated for any oxidation , the newer equipment will probably require a smaller breaker.. After this then make your evaluation..

[shigadeyo]

Average electric cost for the past 3 years has been $3600/year.

No NG available at the road; would have to get propane tank for dual fuel.

Completely new circuits will be run for the new system and 1 will actually be larger than existing.

I have a detailed GEOLINK report for the 3 ton, dual compessor, 4 ton loop proposal.

Cost for unit and all ductwork, zoning, etc. after all rebates and tax credits is twice as much as a replacement electric heat pump without any ductwork changes quoted 2 hears ago.

[shigadeyo]

Also, our location is Southwest Ohio.

Please elaborate on possible house issues...

[jerryd_2008]

Average electric cost for the past 3 years has been $3600/year.

...

WOW, $300/month! What kind of cooling and heating temps do you use? Any big non-HVAC costs in there? Have you compared your costs to neighbors with similar size and style?

May be an apple to oranges compare but our 3500+ sqft 2-story house built in 1994 in NW Arkansas with very large under the house garage (almost like a good sized basement) has consistently run $1500-1600/year total NG and electric. But we do set cooling at 78-79 and heating to 69-70. Summers can get hot but winter is only 2 months with a few below 10 F days. Don't have new costs for the new DFHP we installed last July.

Also, our location is Southwest Ohio.

Please elaborate on possible house issues...

At those costs, I would definitely look at blower door test along with infrared scanning for problem areas to address. What's the attic insulation like? It's amazing what an additional 6" of cellulose over the top of any fiberglass along with a dozen tubes of caulk and cans of foam and some new door gaskets can do and at a reasonable cost.

[shigadeyo]

Oh, I completely forgot to say the temps that the thermostat is set on...

63 degrees in the Winter!
76 degrees in the Summer!

[jerryd_2008]

Oh, I completely forgot to say the temps that the thermostat is set on...

63 degrees in the Winter!
76 degrees in the Summer!

Those seem pretty reasonable to me. Doesn't appear that you have unreasonable expectations, but I'm just a HO. Can't you just open the door in the winter and maintain 63?

What about the other questions?

[INTECHBILL]

A Heat-Loss / Heat-gain calculation would be worth it and a plus if your going for a rebate or tax credit . & you could save the headache of firing gas if you considered a water source or geo Heat-pump

[shigadeyo]

Based on your recommendations, I have contracted with an independent local organization (http://www.homeenergycheckup.com) to come in and to a full energy audit complete with blower door test, thermal imaging, etc. to figure out my current state and what is recommended for improvements before I pull the trigger on a complete geothermal overhaul. I'll let you know how it turns out! Thanks again for the help.

[djastram]

Don't forget about this...
http://www.waterfurnace.com/event/

[shigadeyo]

Don't forget about this...
http://www.waterfurnace.com/event/

Yes, but I am replacing an air-to-air heat pump. Unfortunately, the WaterFurnace rebate is only on replacing an existing geothermal heat pump...

[no_klu]

It sounds like you have a building envelope problem for sure and maybe another one as well. Improving the insulation of your house (in attic, between floor of MBR and garage, etc) plus stopping drafts will make a big difference in the heat loss/gains of your house. This work should be done before you have a heat loss/gain calculation done so the the sizing of the new equipment (tons of cooling/heating) reflects the needs of the house. Using the heat loss/gain calc's will allow the new duct system to be sized for the cfm needs of each room to provide the best comfort for you. If a room has a smaller heat gain/loss then smaller pipe/duct is needed for that room. Yes it worth the extra costs to have 1 zone per floor instead of main and bsmt floors on the same zone. Each floor of a home has different heat gains/losses. A 1 zone per floor system can respond to the different needs much more comfortably. Part for your high electric bills may be that some of the R22 (Freon) has leaked out of your H/P and it is no longer operating at its design capacity. This results in the system running much longer then it should in order to satisfy the T-stat.

[shigadeyo]

I forgot to post the results and recommendations from the energy audit...

Blower Door: 2300 cfm @ 50 Pa
Building Leakage: .34

Biggest recommendations included:

Insulate basement walls to R13 from top to bottom
Seal airleaks
Insulate attic (from R20 to R50)

[jerryd_2008]

...

Biggest recommendations included:

Insulate basement walls to R13 from top to bottom
Seal airleaks
Insulate attic (from R20 to R50)

None of those sound that expensive. You might do them yourself if you are that type. Air leaks are a couple of tubes of caulk and a few cans of foam if you documented where the leaks are. The current R20 in the attic is very low IMO. I had a company blow in 6" extra cellulose right over my fiberglass. Works great! You may consider more though. Don't know how much you need to get R30 increase. R50 seems a big much - don't know where the diminishing returns set in. Any insulation guys out there?